Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

vscode on save got incredibly slow after rubocop 1.90 upgrade + UseProjectIndex

Open
  • Is something wrong?
#4,208 3 comments 0 reactions 0 assignees View on GitHub

Maintainers usually reply within 1 day

Nobody has claimed this yet.

Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Active
Tech stack
ruby, vscode
Domain
developer-experience, performance, tooling

Research direction

Start with the Ruby LSP RuboCop-on-save integration and its RuboCop CLI invocation, then compare behavior with RuboCop 1.90's UseProjectIndex and rubydex documentation. Done means the reindexing slowdown is reproduced or bounded and the integration documents or avoids redundant project indexing; no file or test is named.

Written by the indexing model from the issue text.

Description

bug pinned
Description
Ruby LSP Information

### Ruby LSP Information

#### VS Code Version

1.137.0

#### Ruby LSP Extension Version

0.10.6

#### Ruby LSP Server Version

0.26.11

#### Ruby LSP Add-ons

- Tapioca (0.1.3)
- Ruby LSP Rails (0.4.8)
- RuboCop (1.90.0)

#### Ruby Version

4.0.6

#### Ruby Version Manager

asdf

#### Installed Extensions

<details>
<summary>Click to expand</summary>

- claude-code (2.1.270)
- remote-containers (0.469.0)
- ruby-extensions-pack (0.1.14)
- ruby-lsp (0.10.6)
- sorbet-vscode-extension (0.3.47)
- terraform (0.2.5)
- vim (1.32.4)
- vscode-containers (2.5.0)
- vscode-jsonnet (0.7.4)
</details>

#### Ruby LSP Settings

<details>
<summary>Click to expand</summary>

##### Workspace

```json
{
  "indexing": {
    "excluded_patterns": [
      "/bin/**",
      "/cypress/**",
      "/front-end/**",
      "/kubernetes/**",
      "/public/**",
      "/secrets/**",
      "/semgrep/**"
    ],
    "excluded_gems": [
      "annotate",
      "better_errors",
      "binding_of_caller",
      "brakeman",
      "bullet",
      "bundler_audit",
      "danger",
      "danger-rubocop",
      "debase",
      "guard",
      "guard-rspec",
      "knapsack_pro",
      "listen",
      "parallel_tests",
      "rspec_junit_formatter",
      "rubocop",
      "rubocop-daemon",
      "rubocop-rails",
      "rubocop-rspec",
      "ruby-debug-ide",
      "ruby-lsp",
      "solargraph",
      "spring-commands-rpsec",
      "squasher",
      "super_diff"
    ]
  }
}
User
{
  "enabledFeatures": {
    "codeActions": true,
    "diagnostics": true,
    "documentHighlights": true,
    "documentLink": true,
    "documentSymbols": true,
    "foldingRanges": true,
    "formatting": true,
    "hover": true,
    "inlayHint": true,
    "onTypeFormatting": true,
    "selectionRanges": true,
    "semanticHighlighting": true,
    "completion": true,
    "codeLens": true,
    "definition": true,
    "workspaceSymbol": true,
    "signatureHelp": true,
    "typeHierarchy": true
  },
  "featuresConfiguration": {},
  "addonSettings": {},
  "rubyVersionManager": {
    "identifier": "auto"
  },
  "customRubyCommand": "",
  "formatter": "auto",
  "linters": null,
  "bundleGemfile": "",
  "testTimeout": 30,
  "pullDiagnosticsOn": "both",
  "useBundlerCompose": false,
  "bypassTypechecker": false,
  "rubyExecutablePath": "",
  "indexing": {
    "excluded_patterns": [
      "/bin/**",
      "/cypress/**",
      "/front-end/**",
      "/kubernetes/**",
      "/public/**",
      "/secrets/**",
      "/semgrep/**"
    ],
    "excluded_gems": [
      "annotate",
      "better_errors",
      "binding_of_caller",
      "brakeman",
      "bullet",
      "bundler_audit",
      "danger",
      "danger-rubocop",
      "debase",
      "guard",
      "guard-rspec",
      "knapsack_pro",
      "listen",
      "parallel_tests",
      "rspec_junit_formatter",
      "rubocop",
      "rubocop-daemon",
      "rubocop-rails",
      "rubocop-rspec",
      "ruby-debug-ide",
      "ruby-lsp",
      "solargraph",
      "spring-commands-rpsec",
      "squasher",
      "super_diff"
    ]
  },
  "erbSupport": true,
  "featureFlags": {},
  "sigOpacityLevel": "1"
}
```
Reproduction steps

The reproduction is hard without a sufficiently large app. As mentioned above, after upgrading to rubocop 1.90, and enabling the UseProjectIndex config, which enables their rubydex integration, rubocop-on-save suddenly started taking >30s, up to the point where I'm constantly pressing "Skip" when running the rubocop formatter.

My understanding is that ruby-lsp's rubocop integration just runs rubocop cli command on save. My guess, and based on what's written here, is that when the integration is enabled, rubocop will reindex the whole project before running cops.

This may not be a ruby-lsp problem, but it does result in visible DX impact for ruby-lsp users, which will perceive the tool as being slow. This being an experimental flag, the goal is to document this, so that the integration can be reworked so that rubocop's add-on piggy backs on ruby-lsp's already indexed workspace and skips this step.

Dominant language
Ruby
Stars
2k
Forks
282
Avg merge
12h 23m
Merged PRs (30d)
9

Getting set up

Open in Codespaces

Starts the project's dev container in your browser, under your own GitHub account.

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from Shopify/ruby-lsp

All issues in Shopify/ruby-lsp

Similar issues

More Ruby issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.